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Date:   Thu, 20 Jun 2019 18:19:20 -0700
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Subject: [PATCH V33 09/30] kexec_file: Restrict at runtime if the kernel is
 locked down
From:   Matthew Garrett <matthewgarrett@google.com>
To:     jmorris@namei.org
Cc:     linux-security@vger.kernel.org, linux-kernel@vger.kernel.org,
        linux-api@vger.kernel.org, Jiri Bohac <jbohac@suse.cz>,
        David Howells <dhowells@redhat.com>,
        Matthew Garrett <mjg59@google.com>, kexec@lists.infradead.org
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From: Jiri Bohac <jbohac@suse.cz>

When KEXEC_SIG is not enabled, kernel should not load images through
kexec_file systemcall if the kernel is locked down.

[Modified by David Howells to fit with modifications to the previous patch
 and to return -EPERM if the kernel is locked down for consistency with
 other lockdowns. Modified by Matthew Garrett to remove the IMA
 integration, which will be replaced by integrating with the IMA
 architecture policy patches.]

Signed-off-by: Jiri Bohac <jbohac@suse.cz>
Signed-off-by: David Howells <dhowells@redhat.com>
Signed-off-by: Matthew Garrett <mjg59@google.com>
Reviewed-by: Jiri Bohac <jbohac@suse.cz>
cc: kexec@lists.infradead.org
---
 kernel/kexec_file.c | 6 ++++++
 1 file changed, 6 insertions(+)

diff --git a/kernel/kexec_file.c b/kernel/kexec_file.c
index 67f3a866eabe..455f4fc794f3 100644
--- a/kernel/kexec_file.c
+++ b/kernel/kexec_file.c
@@ -239,6 +239,12 @@ kimage_file_prepare_segments(struct kimage *image, int kernel_fd, int initrd_fd,
 		}
 
 		ret = 0;
+
+		if (security_is_locked_down(LOCKDOWN_KEXEC)) {
+			ret = -EPERM;
+			goto out;
+		}
+
 		break;
 
 		/* All other errors are fatal, including nomem, unparseable
-- 
2.22.0.410.gd8fdbe21b5-goog